The present invention proceeds from a
method for allocating identifiers, that are contained in signals issued by transmitters arranged in a tire pressure monitoring system,
comprising a pressure sensor, a transmitter and a transmission antenna on each of a number of vehicle wheels, one or more receiving antennas on the vehicle body, and an electronic receiving and analysis system connected to such antennas by wire,
to the positions of the wheels on which the transmitters are arranged, by picking up the signals, containing the identifier, by the one or more receiving antennas, transmitting them to the electronic receiving and analysis system and analyzing them by means of the latter with respect to their identifier, as prior art.
A method of this kind has been known from DE 196 08 478 A1. The known tire pressure monitoring system comprises on each wheel of a vehicle a pressure sensor, an electronic analysis circuit connected to the pressure sensor, a transmitter, a transmission antenna and a battery which latter supplies the electronic systems on the wheels (hereinafter referred to as wheel electronics) with current. Provided on the vehicle body, adjacent the wheels, are receiving antennas which are connected via cable to a central receiving and analysis circuit (hereinafter referred to as central electronic analysis system).
A problem encountered with such tire pressure monitoring systems is unequivocal allocation of the transmitters to the respective position of the wheel on the vehicle. To solve this problem, the transmitters generate a signal divided into four segments, consisting of preface, identification signal, measurement signal, and conclusion. The central electronic system can recognize the position of the transmitting wheel of the vehicle based on the identification signal (identifier). Doing so, however, requires previous unequivocal allocation of the identifier to the respective wheel position and storing of that allocation in the central electronic analysis system. DE 196 08 478 A1 discloses a possibility of performing that allocation automatically, based on the signals transmitted by the wheel electronics, after the initial assembly of the wheels on the vehicle or after a wheel change. To this end, the intensity of the signals received is analyzed statistically: Although each receiving antenna receives signals from all transmitting vehicle wheels, one starts out from the assumption that the signals obtained from the wheel the closest to the respective receiving antenna will be received with the greatest intensity, taking the statistical mean value.
A similar allocation system is known from DE 196 08 479 A1.
The known allocation methods are connected with the disadvantage that they cause considerable costs in connection with the tire pressure monitoring system because a separate receiving antenna must be provided in the neighborhood of each wheel, and must be connected via an antenna cable to the central electronic analysis system in the vehicle.
As a solution to the problem to provide a lower-cost possibility of achieving automatic allocation of the identifiers, that have been transmitted by the wheel electronics, to specific wheel positions, DE 197 35 686 A1 discloses a method with the features specified in the preamble of claim 1.
DE 197 35 686 A1 provides to configure the wheel electronics arranged on each wheel in such a way that it will not only measure the tire pressure and transmit it to the central electronic analysis system, but will in addition determine information on the moving condition of the wheel and transmit that information to the central electronic analysis system. Based on the moving condition of the wheel the central electronic analysis system will then derive a datum on the position of the respective wheel on the vehicle.
According to the invention, useful information on the moving condition of the wheel is derived from the acceleration occurring on the wheel. The acceleration signals provided by an acceleration sensor connected to the wheel electronics are either evaluated in the wheel electronics, whereafter the results of such evaluation are transmitted to the central electronic analysis system, or are inserted by the wheel electronics into the signal to be regularly transmitted and are then transmitted to and evaluated in the central electronic analysis system.
Miniaturized semiconductor-based acceleration sensors that can be integrated at relatively low cost into the wheel electronics anyway required, are available in the market. The additional input to the wheel electronics connected with such integration is considerably lower than the costs saved by the elimination of receiving antennas and their cabling.